Dorsal Quad Surfboard Fin Box Set [Black - White] Quad Fin Box Set [Black - White] Quad IFT production set. This comes with 2 x 3/4" and 2 x 1/2" side boxes. Included screws. Introducing the new IFT Fin boxes from DORSAL with Interwoven Fiber Technology (IFT). The lightest strongest fin system in the world now bonds even better to the skin of your board than the leading brands. The "X" cutouts in the IFT Box create a stronger bond while decreasing weight because resin is interwoven between the flange of the box and the fiberglass of the board. The interwoven resin forms cross pillars that lock the fiberglass to the flange with a solid physical connection. Our IFT boxes are all made right here in California.